Interlocking control for mine-hoists.



C. L. PERRY.

LNTERLOCKING CONTROL FOR MINE HOISTS,

APPUCATIOH FILED MAR.25. 1918.

1,273,661. Patented July 23,1918..

Inventorar es Ll er-r-g,

His fitter-neg.

UNITED STATES PATENT OFFICE.

CHARLES Ia. PERRY, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. A

INTERLOCKING CONTROL FOR MINE-HOISTS.

Specification of Letters Patent.

Patented July 23, 1918.

To all whom it may concern:

Be it known that I, CHARLES L. PERRY, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Interlocking Controls for Mine-Hoists, of which the following is a specification."

My invention relates to the control of motor driven hoists and has for its object the provision of improved means whereby. RS the hoist may be started, stopped and generally controlled in a reliable, simple and eflicient manner.

My invention relates more specifically to the control of mine hoists in which there is a landing platform for men at a lower elevation than the point at which the coal or other material is dumped. Serious accidents have been caused by carrying men beyond their landing platform and into the dump,. and various methods have been suggested for providing protection against such accidents which, however, have not completely insured the stopping of the hoist at the mens platform in case of carelessness of the operator. One of the objects of my invention is to provide improved means for insuring the stopping of the hoist at the mens platform and eliminate such accidents.

In carryin out my invention, I provide means whereby when men arewto be carried up in the cage, a signal is given by an operator at the bottom of-the shaft to the hoist operator who is generally stationed near the mens landing. In giving this signal, he also makes certain connections which make it impossible for the operator to start the hoist until he performs some act, such as the throwing of a switch, which will render the limit switch at the mens landing effective to stop the hoist in case the operator fails to do so. Other objects and purposes of my invention will appear in the course of the following specification in which I have described my invention as embodied in concrete form for purposes of illustration.

The invention will best be understood by reference to the accompanying drawin in which it is diagrammatically illustrate as applied to a balanced hoist having two cages G and C arranged to move in opposlte d1- rections between a lower or loading level L and an unloading platform or dump L winding of the drums Located some distance below the dump is the mens landing platform L at which it is necessary to insure the stopping of an upward bound cage carrying men.

The cages are suspended from drums mounted on a shaft driven by the electric motor M, here shown as a three phase induction motor receiving current from a three phase supply line S, through electromagnetically operated reversing switches adapted to deliver current to the motor for either direction of rotation for hoisting or lowering the cages. The actuating of the'reversing switches RS is controlled by a master controller MC, the contacts of which are arranged to close the circuit of the actuating coil of either of the "reversing switches tozcause the motor to be connected to the supply line for the desired direction 4 of rotation. The speed of the motor may be controlled through the variable resistance R.

Located above the limit switches A'A for preventing overand associated with these limit switches are the usual backing out switches BB, which in case either of said overwind limit switches are tripped by a cage, through neglect on the part of the hoistoperator to stop the motor, may be manipulated to release the emergency brake and make possible the startin of the motgr in the reverse direction for acking out.

All of the features so far described are I commonly embodied in such hoist equipments and form no part of my invention.

- The novel features of my invention, designed to insure the stopping of the cages at the mens platform L, comprise the triple pole switch D located at the loading level L; the triple pole switch E located at signaling means such as lamps G located atv the hoist operators station and included in a circuit adapted to be closed by the switch D at the loading level; and an emergency brake H associated with the drum shaft, said brake being normally maintained released by its magnetizing coil, but adapted to be applied in emergency by the opening of the circuit of its coil by the tripping of the dump are the usual various limit switches under certain conditions.

During normal hoisting operation, when men are not being carried, the elements and connection are maintained as shown in the drawing, the motor being started and stopped by the hoist operator by means of the master controller MC. Under these conditions the tripping of'the limit switches F-F' asthe cages approach the mens platform L, does not affectthe motor control circuits, which are by-passed about these limit switches through the leads 1 and 2 respectively, and through the switch D.

As stated above the emergency brake H is normallyreleased, as its operating coil is maintained energized, a separate service brake not shown in the drawing, being generally used. With the various switches in the positions illustrated, the brake coil is energized by a circuit across the supply line, including the lead 3, limit switches A'A, the brake coil, lead 4, switch D and lead 5.

When switch D is open, the brake coil is energized by a circuit through contacts closed in the off position of the master controller MC, the brake coil, the limit switches AA' and lead 3. In the course of this normal operation of the hoist, the hoist control operator is notified by an operator at the loading level, by any suitable signaling means, not illustrated in the drawing, when the cages are loaded and ready to be hoisted.

When, however, men are/to be hoisted, the operator at the loading level signals the hoist control operator to that effect and that the cage containing the men is ready to be hoisted, by closing switch D on contact 6,

thus completing a circuit through the signal lamps G. One of the lamps. in this signal circuit may be located at the loading level adjacent the switch D, to indicate to the operator at this point that the signal circuit is properly closed.

The closing of the switch D on the signal contact 6 opens the by-pass circuits 1 and 2 around the limit switches F-F and makes it impossible for the hoist control operator to start the motor by operating the master controllen MG, until he has first closed switch E on'the contacts 7, 8, 9 or contacts 7 8, 9, and thus made possible the closing of the motor control circuits through leads 10 or 11 and contacts 12 or 12 of the respective limit switches F, F. The closing of switch D on the signal contact 6, and the closing of switch E on contact 9 or on contact, transfers the emergency brake coil to'a circuit from lead 4 either through contact 13 of limit switch F, or through contact 13 of limit switch F, depending upon the positions of'the respective cages Assume that switch D has been closed on contact 6 to signal the control operator that cage G is ready to hoist men and that the control operator, after closing. switch E on contacts 7, 8, 9, turns master controller MC to the right to close an energizing circuit for the operating coil 14' of the reversing switch RS, through the contact segments 15; the motOr now starts hoisting cage G and lowering cage C.

As cage C passes the mens platform L it engages the lever of limit switch F, throwing it to the position corresponding to that in which limit switch F is shown, and as cage C reaches the mens platform L it trips limit switch F and opens the motor control circuit at contact 12, thus deenergizing the operating coil 14 of the reversing switch RS to open the motor circuit, and also opens the brake coil circuit at contact 13 causing an application of the emergency brake, insuring the stopping of the motor if the control operator, through carelessness has neglected to throw the master controller to the off position and apply the service brake. At this time the cage C havingreached and beenstopped at the mens platform L, the cage C is still some distance above the loading level L; in order to start the motor to lower cage C to the loading level and simultaneously hoist. cage C to the dump L it is necessary for the control operator to throw switch E over to contacts 7 8, 9, to close the motor control circuit through lead 16 and contacts 17 of limit switch F which are now closed.

The contacts ofthe limit switches F and F- should preferably be so proportioned and arranged that, when the respective cage C or C is stopped by the hoist operator at the mens platform, they simultaneously make contact with all fingers to prevent an unnec embodiment thereof; but I desire to have it Y understood that the arrangement shown isonly illustrative and that the invention can be carried out by other means and therefore I aim in the appended clalms to cover all modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States 1s:-

1; The combination with a motor driven hoist having a loading platform and two unloading platforms, one at ahigher elevation than the other, of a limit switch at the 3. The combination with a motor drivenv hoist having a loading platform and two unloading platforms, one at a higher elevation than the other, of a switch remote from the. loading platform and controlled by .the .operator, a switch at the loading platform for signaling to the operator, a limit switch at the lower unloading platform and connections including said two switches for rendering the limit'switch effective to stop the motor.

4. The combination with a motor driven ihoist' having a loadingplatform and two nnloading platforms, one at a higher elevation than the other, of'a switch at the loading platfornifa switch remote from the loading platform and controlled by the operator, a limit switch at the lower unloading platform whichmay or may-not stop the motor depending upon the condition of said switches, and means whereby when the switch at the loading platform is moved to itsefl'ective position with reference to the limit switch the motor can only be started after the operators switch has been moved to' correspond with the switch at the loading platform and render the limit switch operative to stop the motor.

-5. The combination with a motor driven hoist having a loading platformand two unloading platforms, one at a higher elevationthan the other, of a limit switch at the lower unloading platform, a switch remote from the loading platform and controlled by the operatorfor governing the effectiveness of the limit switch to stop the motor, a switch at the loading platform for signalof a switch at the load-' switch at the loading platform is moved to signal the operator and render the limit switch effective, the motor can only be started after the operators switch has been moved to correspond to the switch at the loading platform and render the limit switch operativeto stop the motor.

6. The combination with a motor driven hoist having a loading platform and two unloading. platforms, one at a higher elevation than the other, of a switch at the loading platform, a switch remote from the loading platform and controlled by the operator, a limit switch at the lower unloading platform and controlled conjointly by said two switches to, render it effective to stop the motor and connections whereby after the motor has been stopped by the limit switch it cannot be again started to carry the hoist to the upper unloading platform until said operators switch is again operated.

7. The combination with a motor driven balanced hoist having a loading platform and two unloading platforms, one at a higher elevation than the other, of two limit switches at the lower unloading platform one operated by each cage in its hoisting movement and means controlled jointly from the loading platform and from the vicinity of the lower unloading platform for rendering either limit switch effective to stop the motor depending upon which cage is being hoisted.

8. The combinationwith a motor driven balanced hoist having a loading platform and two unloading platforms, one at a higher elevation than the other, of a switch at the loading platform, a switch remote from the loading platform controlled by the operator, two 7 unloading platform one controlled by each cage in its hoisting movement and connections'including said two switches for renders" ing either limit switch effective to stop the motor depending upon which cage .is being CHARLES L. PERRY.

limit switches at the lower 

